diff --git a/.zuul.yaml b/.zuul.yaml
index 93b1401e37..d6419c8151 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -10,11 +10,16 @@
       jobs:
         - openstack-tox-validate
         - releases-tox-list-changes
-        - build-openstack-sphinx-docs
+        - build-openstack-sphinx-docs:
+            vars:
+              sphinx_python: python3
+
     gate:
       jobs:
         - openstack-tox-validate
-        - build-openstack-sphinx-docs
+        - build-openstack-sphinx-docs:
+            vars:
+              sphinx_python: python3
     release-post:
       jobs:
         - tag-releases
diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 0000000000..349c9e8bd1
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1,6 @@
+# Packages required for building docs
+
+sphinx>=1.6.2  # BSD
+oslosphinx>=4.7.0  # Apache-2.0
+sphinxcontrib.datatemplates>=0.1.0  # BSD License
+icalendar>=3.10  # BSD
diff --git a/tox.ini b/tox.ini
index 6076eee349..0adce92868 100644
--- a/tox.ini
+++ b/tox.ini
@@ -59,8 +59,11 @@ commands = {toxinidir}/tools/build_tag_history.sh {toxinidir}
 #commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:docs]
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d doc/build/doctrees -b html doc/source doc/build/html
-deps = .[sphinxext]
 
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.